JBL 100 Classic or Klipsch Heresy III?

2 entirely different animals there...the Heresy IIIs are extreme efficiency (99db) horns with no low bass (I own a pair and use 2 REL subs with 'em as they go down to about 58hz before the bass drops off...the bass they do put out is very accurate though), and the JBLs are 90db and more "normal" but twice as expensive as the Heresy IIIs. Heresy IIIs do seem to like boundaries as that reinforces the bass, and since they use horns they project away from the box to minimize room issue in the upper frequencies. Note that all of this requires listening to the things someplace as your ears are what matters, and note that at 4 grand for the JBLs you can look at a myriad of speakers that would also work great. Good luck!

A pair of Heresy, with your PrimaLuna, would be awesome. As mentioned above, efficient, and an easy load. The PrimaLuna would thrive, never break a sweat, as will the Heresys. Heresy against a wall. No problem. Need a sub or 2. No problem, and still less than the L100s. Not only do the horns minimize cabinet diffraction, as wolf stated, they also minimize side wall reflections. However, I must be honest here. If you have never read any of my posts here on the "gon, I am likely the largest Klipsch Heritage fan here, of which the Heresy is a member. The bass on the JBLs extends a little deeper, but the quality of the Heresy will be faster and tighter, especially using tubes, as the designs are : ported ( JBL ), vs. air suspension ( Heresy ). And my opinion is based on experience. However, $4K is a good amount of money to spend, and there is a lot available, again, as wolf indicated. Enjoy ! MrD.